Updated

After years of flu shot shortages and production delays, vaccine makers on Thursday projected that supplies will reach a record 100 million doses for the coming season and create a possible surplus.

Public health officials want to build demand for the shots to keep the nation's vaccine infrastructure strong enough to cope with a possible flu pandemic. They worry that if not enough people get the shots, manufacturers won't want to keep producing that much vaccine.

"If we don't do this well, it's going to be harder to convince manufacturers that it's worth it," said Kathleen Coelingh, senior director of scientific affairs for MedImmune Inc., of Gaithersburg, Md., which makes a flu vaccine nasal spray. "We need to be ready for a pandemic and the only way we can do that is to be ready every year."

The vaccine is made fresh each year to match the flu virus types expected to circulate in the coming season, and unused vaccine from the previous season must be tossed out. It takes nine months to make the vaccine each year, so new supplies can't be turned out quickly.

Officials met with doctors and manufacturers Thursday at the National Influenza Vaccine Summit in Chicago to discuss ways to drum up takers for the shots and the nasal spray vaccine.

Ariyapadi Krishnaraj, vice president for marketing at vaccine maker Novartis AG, said one way to increase demand is to remind people that getting the shots makes them less likely to pass the flu to vulnerable loved ones, such as elderly relatives.

"Fear of infecting others is a powerful motivator," he said.

The record supply poses a challenge far different from two years ago when one company was barred from shipping nearly half of U.S. vaccine orders because of contamination at a Liverpool, England factory. That resulted in long lines and shortages.

One development that could boost demand is an expected expansion by the Centers for Disease Control and Prevention of recommendations on who should get flu shots. The expansion would bring the total number to 218 million adults and children, or 73 percent of the U.S. population.

In February, an advisory panel said children ages 2 to 5 also should get flu shots. That expansion was unanimously approved by the Advisory Committee on Immunization Practices and the CDC is expected to adopt the panel's advice.

Flu vaccines now currently recommended for children ages 6 months to 23 months, pregnant women, people 65 and older and people of all ages with chronic health conditions. They are also recommended for health care workers and people who live with those who are at risk.

Last year, about 86 million doses of flu vaccine were produced and 81 million were distributed.